machine/stm32: add support for stm32f103xx UART

Signed-off-by: Ron Evans <ron@hybridgroup.com>

src/machine/machine_stm32.go

@@ -4,17 +4,8 @@ package machine
 
 // Peripheral abstraction layer for the stm32.
 
-import (
-	"device/stm32"
-)
-
 type GPIOMode uint8
 
-const (
-	GPIO_INPUT  = 0 // Input mode
-	GPIO_OUTPUT = 2 // Output mode, max speed 2MHz
-)
-
 const (
 	portA = iota * 16
 	portB
@@ -24,54 +15,3 @@ const (
 	portF
 	portG
 )
-
-func (p GPIO) getPort() *stm32.GPIO_Type {
-	switch p.Pin / 16 {
-	case 0:
-		return stm32.GPIOA
-	case 1:
-		return stm32.GPIOB
-	case 2:
-		return stm32.GPIOC
-	case 3:
-		return stm32.GPIOD
-	case 4:
-		return stm32.GPIOE
-	case 5:
-		return stm32.GPIOF
-	case 6:
-		return stm32.GPIOG
-	default:
-		panic("machine: unknown port")
-	}
-}
-
-// Configure this pin with the given configuration.
-func (p GPIO) Configure(config GPIOConfig) {
-	// Enable clock.
-	// Do this always, as it isn't known whether the clock has already been
-	// enabled.
-	stm32.RCC.APB2ENR |= stm32.RCC_APB2ENR_IOPCEN
-
-	// Configure the GPIO pin.
-	port := p.getPort()
-	pin := p.Pin % 16
-	pos := p.Pin % 8 * 4
-	if pin < 8 {
-		port.CRL = stm32.RegValue((uint32(port.CRL) &^ (0xf << pos)) | (uint32(config.Mode) << pos))
-	} else {
-		port.CRH = stm32.RegValue((uint32(port.CRH) &^ (0xf << pos)) | (uint32(config.Mode) << pos))
-	}
-}
-
-// Set the pin to high or low.
-// Warning: only use this on an output pin!
-func (p GPIO) Set(high bool) {
-	port := p.getPort()
-	pin := p.Pin % 16
-	if high {
-		port.BSRR = 1 << pin
-	} else {
-		port.BSRR = 1 << (pin + 16)
-	}
-}